The morphology of ALN layers grown by Metalorganic Chemical Vapor Deposition on nano-structured NP-Si(001) substrates coated with SiNx has been studied using atomic force microscopy. The AlN layers grown on the SiNx/NP-Si(100) template demonstrate a surface roughness 3.8 times less than those obtained on NP-Si(100), and are close to the roughness value for the AlN layer grown on a flat Si(111) substrate. It has been proposed a model to explain the differences in the formation of the surface morphology of AlN layers on the NP-Si(100) substrate and the SiNx/NP-Si(100) template.

Study of Ga 2 O 3 deposition by MOVPE using trimethylgallium and oxygen was performed in a wide temperature range. It was found that for Ga 2 O 3 deposition rate vs temperature dependence is very close to the TMGa pyrolysis in nitrogen. Kinetically-limited range for these processes corresponds to 550-700 o C, that is 150 o C higher, then for GaN deposition in the same reactor. Keywords: gallium oxide, MOVPE

It has been studied the morphology of the surface of the semipolar gallium nitride layers synthesized on nano-pattemed Si(100) or Si(113) substrates with a V-shaped or U-shaped surface profile, respectively. The morphology of the surface of the semipolar layers indicates that the different height-to-width ratio of the GaN(11-22) and GaN(10-11) blocks is associated with a higher growth rate of the GAN(11-22) face than GaN(10-11) and with different growth rates of the semipolar and polar crystal faces during the nucleation of the layer on a nano-patterned substrate.

scanning electron microscopy was used to study of the initial stages of the formation of a semipolar GaN(11 2̅ 2) layer during Metalorganic Chemical Vapor Deposition on Si(113) substrates, on the surface of which U-shaped grooves with element sizes <100 nm (NP-Si(113)) were formed. It was found that NP-Si(113) substrates with a buffer AlN layer stimulate the formation of islands faceted by the planes m-GaN, c‑GaN. It is shown that there is a predominant growth of the m-GaN facet in comparison with c-GaN. The experimental results correspond to the Gibbs-Curie-Wolff selection principle, but taking into account elastic stresses in the c-GaN plane.

The article reports the growth of semi-polar GaN(11-22) layers using epitaxy from metal organic compounds on a nanostructured NP-Si(113) substrate. It was shown that upon the emergence of an island layer, elastic deformed structures of GaN(11-22)/NP-Si(113) form a nano-meter compliant silicon layer on a substrate while elastic stresses conditioned by the difference of temperature coefficients of GaN and Si in such a structure decrease

Scanning electron microscopy was used to study of the initial stages of the formation of a semipolar GaN(1122) layer during Metalorganic Chemical Vapor Deposition on Si(113) substrates, on the surface of which U-shaped grooves with element sizes <100 nm (NP-Si(113)) were formed. It was found that NP-Si(113) substrates with a buffer AlN layer stimulate the formation of islands faceted by the planes m-GaN, c-GaN. It is shown that there is a predominant growth of the m-GaN facet in comparison with c-GaN.The experimental results correspond to the Gibbs--Curie--Wolff selection principle, but taking into account elastic stresses in the c-GaN plane. Keywords: semipolar gallium nitride, nano-structured substrate, silicon.

scanning electron microscopy was used to study of the initial stages of the formation of a semipolar GaN(1122) layer during Metalorganic Chemical Vapor Deposition on Si(113) substrates, on the surface of which U-shaped grooves with element sizes <100 nm (NP-Si(113)) were formed. It was found that NP-Si(113) substrates with a buffer AlN layer stimulate the formation of islands faceted by the planes m-GaN,c-GaN. It is shown that there is a predominant growth of the m-GaN facet in comparison with c-GaN. The experimental results correspond to the Gibbs-Curie-Wolff selection principle, but taking into account elastic stresses in the c-GaN plane.

Методом растровой электронной микроскопии изучались начальные стадии формирования полуполярного GaN(1122) слоя при эпитаксии из металлоорганических соединений на подложках Si(113), на поверхности которых сформированы U-образные канавки с размером элементов <100 нм (подложка-NP-Si(113)). Установлено, что NP-Si(113) подложки с буферным слоем AlN стимулируют формирование островков, ограненных плоскостями m-GaN, c-GaN. Показано, что наблюдается преимущественный рост грани m-GaN по сравнению с c-GaN. Экспериментальные результаты соответствуют принципу отбора Гиббса--Кюри--Вульфа, но с учетом упругих напряжений в плоскости c-GaN. Ключевые слова: полуполярный нитрид галлия, нано-структурированная подложка, кремний.

A method for synthesising hexagonal GaN on a Si(113) substrate with a nanostructure of about 75 nm on its surface ( NP-Si(113) substrate) is proposed. It has been established that the method of the metal-organic chemical vapor deposition on such a substrate makes it possible to form a semi-polar layer of GaN(11-22) with half-widths of the X-ray diffraction curve omega(theta) similar to 30 arcmin. It is shown that during epitaxy from organometallic compounds in hydrogen atmosphere at the initial stages of growth the layer orientation is given by the direction of Si(111) plane of nanocanals in NP-Si(113) and the growth rate of GaN layer in (11-22) and (0001) planes direction is comparable.

Results from studying deformation are obtained for semipolar GaN(11–22) grown on a nanostructured Si(113) substrate and polar GaN(0001) grown on a flat Si(111) substrate. A comparison of the structures of semipolar and polar epitaxy reveals a drop in layer deformation resulting from the smaller difference between the coefficients of thermal expansion of the substrate and gallium nitride in the semipolar direction of the crystal than in the polar direction.

This paper proposes a method for synthesis of hexagonal GaN on Si(100) and Si(113) substrates, where nanostructures with an element size less than 100 nm are formed on the surface. It has been established that the method of gas-phase epitaxy from metalorganic compounds in a hydrogen atmosphere on such substrates makes it possible to form semipolar layers of GaN(10-11) and GaN(11-22) with a minimum half-width of the X-ray diffraction swing curve of about 30 arcmin. It is shown that during the formation of a semipolar AlN layer at the initial stage of epitaxy, a corrugated surface is formed on NP-Si(100) from the semipolar planes AlN(10-11) and AlN(10-1-1) with counter-directional c axes. Then, during the growth of the GaN layer, a transition is made from the symmetrical state of the semipolar GaN(10-11) and GaN(10-1-1) planes to an asymmetric state with the orientation of the c axis of the GaN(10-11) layer. That transition is apparently determined by the difference in the values of the surface energy of GaN during epitaxy on the corrugated surface.

It has been studied the morphology of the surface of the semipolar gallium nitride layers synthesized on nano-structured Si(100) or Si(113) substrates with a V-shaped or U–shaped surface profile, respectively. The morphology of the surface of the semipolar layers indicates that the different height-to-width ratio of the GaN(11-22) and GaN(10-11) blocks is associated with a higher growth rate of the GAN(11-22) face than GaN(10-11) and with different growth rates of the semipolar and polar crystal faces during the nucleation of the layer on a nano-structured substrate.

The epitaxial growth of AlN and GaN layers is investigated using metalorganic vapor-phase epitaxy on a Si(100) substrate, on the surface of which a V-shaped nanostructure with elements of sub-100-nm size (NP-Si(100) substrate) is formed. It is shown that a corrugated surface is formed from semipolar AlN(10 $$\bar {1}$$ 1) planes with opposite axes of symmetry c during the formation of a semipolar AlN layer at the initial stage of epitaxy. Then, during the growth of the GaN layer, the transition from the symmetric state of two semipolar AlN planes to an asymmetric state with a single orientation of the c axis of the semipolar GaN(10 $$\bar {1}$$ 1) layer occurs, and the c direction in the growing semipolar layer coincides with the direction of the flow of $${\text{N}}_{2}^{ + }$$ ions to the silicon surface during the formation of a nanomask.

Study of Ga2O3 deposition by MOVPE using trimethylgallium and oxygen was performed in a wide temperature range. It was found that for Ga2O3 deposition rate vs temperature dependence is very close to the TMGa pyrolysis in nitrogen. Kinetically-limited range for these processes corresponds to 550-700 C, that is 150 C higher, then for GaN deposition in the same reactor.

Scanning electron microscopy is used for studies of the initial stages of the formation of semipolar AlN (10 $$\bar {1}$$ 1) and AlN (10 $$\bar {1}$$ 2) layers during metal–organic vapor-phase epitaxy on a Si (100) substrate with a surface, on which a V-shaped nanostructure, whose elements are <100 nm in dimensions, is formed (a NP-Si(100) substrate). It is shown that, in the initial stage of epitaxy on the NP-Si(100) substrate, nuclei of AlN crystals are formed and then, depending on the crystallographic orientation of the V walls, crystals faceted by AlN (10 $$\bar {1}$$ 1) or AlN (10 $$\bar {1}$$ 2) planes are formed, correspondingly, on Si (111) or Si (111) misoriented in the [110] direction by 7°.

Continuous monitoring of patient’s state in intensive care units is crucial for displaying critical conditions and identifying signs of clear consciousness. Traditional monitoring on a bedside monitor represents digital value on the screen and has several shortcomings. The observer’s perception of digital information is limited by visual acuity and affects the speed of decision-making. The radio frequency range is increasingly overloaded with the development of Internet of Things devices. It leads to numerous errors in the transmitted data. The developed system is aimed at the comprehensive elimination of the shortcomings through available means. An understandable visualization system is preferred for prompt recognition of changes in the patient’s state, increasing the speed of perception of the observer, and receiving information in the form of a data set. A data transmission system via optical wireless communication is relevant for duplicative channel for displaying and eliminating the shortcomings of systems operating in the radio frequency range. The system being developed is universal and can be used in a wide range of professional fields. In particular, if the use of the radio frequency range is limited and the stability of the data transmission channel to electromagnetic interference is essential.

We study and compare optical microcavities formed by GaN planar nanowires. Nanostructures with structural defects such as stacking faults and without defects are considered. The behavior of an exciton localized in a stacking fault is considered. Different behavior of the photoluminescence intensity and the photoluminescence decay time is observed for the cases under consideration. Theoretical calculations show the localization of the field at the ends of the structure.

Методом растровой электронной микроскопии изучались начальные стадии формирования полуполярных AlN(1011) и AlN(1012) слоев при эпитаксии из металлоорганических соединений на подложке Si(100), на поверхности которой сформирована V-образная наноструктура с размером элементов <100 нм (подложка-NP-Si(100)). Показано, что на начальной стадии эпитаксии на подложке-NP-Si(100) происходит формирование зародышевых кристаллов AlN, а затем в зависимости от кристаллографической ориентации V-стенок формируются кристаллы, ограненные плоскостями AlN(1011) на Si(111) или AlN(1012) на Si(111), разориентированном в направлении [110] на 7o. Ключевые слова: полуполярный нитрид алюминия, наноструктурированная подложка кремния.

The epitaxial growth of AlN and GaN layers was studied by Metalorganic Vapor Phase Epitaxy, on a Si(100) substrate, on the surface of which a V-shaped nanostructure with sub-100 nm element size (NP-Si(100)) was formed. It is shown that a corrugated surface is formed from semipolar AlN(10-11) planes with opposite "c"axes during the formation of a semipolar AlN layer at the initial stage of epitaxy. Then, during the growth of the GaN layer, the transition from the symmetric state of two semipolar AlN planes to an asymmetric state with a single orientation of the "c"-axis of the semipolar GaN(10-11) layer occurs, and the "c" direction in the growing semipolar layer coincides with the direction of the flow of N2+ ions to the silicon surface during the formation of a nanomask.

The results of joint theoretical and experimental studies aimed at revealing features in the Raman spectra, which can be used for evaluation of the interface quality between GaN and AlN layers in short-period GaN/AlN superlattices (SLs) are presented. The Raman spectra for SLs with sharp interface and with different degree of interface diffusion are simulated by ab initio calculations and within the framework of random-element isodisplacement model, respectively. The comparison of the results of theoretical calculations and experimental data obtained on PA MBE and MOVPE grown SLs, leads to conclusion that the spectral region of the A1(LO) confined phonons is very sensitive to the degree of interface sharpness. As a result of comprehensive studies, the correlations between the parameters of the A1(LO) confined phonons and the structure of SLs are obtained. The results of the complex studies can be used to optimize the parameters of the growth process in order to form structurally perfect short-period GaN/AlN SLs.